package com.itcam.kuangstudy.reflection_;

import java.lang.annotation.*;
import java.lang.reflect.Field;

/**
 * Author:Cammy.Wu
 * Date:2024-05-14
 * Description:反射操作注解
 * <p>
 * getAnnotations
 * getAnnotation
 * <p>
 *      TODO：ORM ———— Object relationship Mapping (对象关系映射)
 */

public class ReflectionDemo11 {
    public static void main(String[] args) throws ClassNotFoundException, NoSuchFieldException {
        Class c1 = Class.forName("com.itcam.kuangstudy.reflection_.Puple");

        // 通过反射获得注解
        Annotation[] annotations = c1.getAnnotations();
        for (Annotation annotation : annotations) {
            System.out.println(annotation);
        }

        // 获得注解的value值
        TablePuple tablePuple = (TablePuple) c1.getAnnotation(TablePuple.class);
        String value = tablePuple.value();
        System.out.println("value = " + value);

        // 获得类指定的注解
        Field f = c1.getDeclaredField("name");
        FieldPuple fieldPuple = f.getAnnotation(FieldPuple.class);
        System.out.println(fieldPuple.columnName());
        System.out.println(fieldPuple.type());
        System.out.println(fieldPuple.length());
    }
}

@TablePuple("db_student")
class Puple {

    @FieldPuple(columnName = "db_id", type = "int", length = 10)
    private int id;
    @FieldPuple(columnName = "db_age", type = "int", length = 10)
    private int age;
    @FieldPuple(columnName = "db_name", type = "varchar", length = 3)
    private String name;

    public Puple() {
    }

    public Puple(int id, int age, String name) {
        this.id = id;
        this.age = age;
        this.name = name;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}


// 类名的注解
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@interface TablePuple {
    String value();
}

// 属性的注解
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@interface FieldPuple {
    String columnName();

    String type();

    int length();
}